Heat-transfer characteristics of the top heat mode closed-loop oscillating heat pipe with a check valve (THMCLOHP/CV)

The aim of this study is to investigate the heat-transfer characteristics of a top heat mode closed-loop oscillating heat pipe with a check valve (THMCLOHP/CV). Water and ethanol are used as the working fluids at various working temperatures. The results show that the specific heat flux increases significantly when the working temperature increases and when the aspect ratio of the evaporator length $L_e$ to the pipe diameter $d$ decreases for the pipe filling ratio varying from $30$ to $80\%$. The maximum specific heat flux equal to $786.34$ W/m$^2$ is reached with the use of ethanol as the working fluid at $L_e/d=25$, angle of inclination to the horizontal axis 90$^\circ$, and filling ratio of $80\%$.